A disadvantage of organic nonlinear optical (NLO) materials is often their low physico-chemical stability. One approach to overcoming this is demonstrated by beta-BNPT-DTO, synthesized by the authors and shown in the Figure, in which S...S intermolecular interactions confer stability. The main emphasis of this article, however, is on semiorganic NLO crystals that combine the advantages of organic and inorganic materials.